Download Geologic Change Over Time Study Guide 1. Describe what

Geologic Change Over Time Study Guide
1. Describe what uniformitarianism s and give an example of this process.
Uniformitarianism is the principle that geological processes that happened in the past
can be explained by those same processes that are happening now. Two examples of
this would be a volcanic eruption in the past can be explained by volcanic eruptions
today and steady erosion that occurred in the past can be explained by erosion today.
2. What would be an event that could cause immediate changes in Earth’s global climate?
An asteroid impact would be an example of this. It would eject large amounts of
particulates into Earth’s atmosphere immediately changing the global climate.
3. What would be a type of geologic evidence that could give scientists information about
the effects of an asteroid impact on Earth’s surface?
An asteroid impact would cause large amounts of particulates to be ejected inot the
atmosphere, blocking much of the sun’s energy from the surface of the planet. This
would cause trees to grow more slowly and the rings of the tree would show this
stunted growth.
4. What evidence would show how a sedimentary rock was formed?
The texture or layers of the sedimentary rock can provide clues about how the rock was
formed.
5. What is a trace fossil?
A trace fossil is a fossilized structure, such as a footprint, that formed in sedimentary
rock by animal activity on or within soft sediment.
6. What is a frozen fossil?
A frozen fossil is one that is formed when the organism dies in very cold area and the
tissues freeze which prevents them from decaying.
7. What is a petrified fossil?
A petrified fossil is when the tissues of an organism are replaced by minerals. Petrified
wood is a good example of this type fossil.
8. What is an ice core and what can be learned from them?
An ice core is a long cylinder of ice obtained from drilling through ice caps or ice sheets.
They are used to study the past climates on Earth.
9. Based on current radiometric dating data, about how old is the Earth?
Based on current radiometric dating data, the Earth is approximately 4.6 billion years
old.
10. What two factors would be responsible for sharp, jagged mountains become lower and
more rounded over time?
The two factors that would be responsible for sharp, jagged mountains becoming lower
and more rounded are weathering and erosion.
11. Why are trace fossils more common than full body fossils?
Trace fossils are more common than full body fossils because a single animal can leave
thousands of traces in its lifetime but will leave only one body.
12. What is a type of sedimentary rock that was formed from once-living plants and
animals?
A type of sedimentary rock that was formed from once-living plants and animals is
limestone.
13. Explain how fossils and other materials can tell us about the conditions of an area at
the time it existed. Then explain how you could find the age of these fossils and other
materials.
Fossils can show what the environment was like at the time they existed. For example a
fish fossil would indicate an aquatic environment. A tropical plant fossil would indicate
a tropical past climate. Other materials, such as tree rings, can tell about past growing
conditions. Sea-floor sediments and ice cores can tell us the past chemical compositions
of the ocean and atmosphere. Ages of these can be found by radiometric dating
techniques. For organic materials, radiocarbon dating could be used but is only accurate
for organisms 45,000 years ago to the present.
14. What is a fossil?
A fossil is the remains of a once-living organism found in layers of rock, ice, or amber.
15. What is the theory that states Earth’s lithosphere is made up of large plates that are in
constant motion?
The theory of plate tectonics explains large-scale movements of the Earth’s lithosphere
on top of the asthenosphere. It also explains continental drift, mountain building,
rifting, and events such as earthquakes.